ML20086B100
| ML20086B100 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 09/03/1976 |
| From: | Brey H, Hillyard H, Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | |
| Shared Package | |
| ML20086B083 | List: |
| References | |
| AO-267-74-21C, NUDOCS 8311170054 | |
| Download: ML20086B100 (4) | |
Text
. - _ -.
- - -. - - ~ _ -
7 O
O u
REPORT DATE:
Sentenber 3. 1976 ABNORMAL OCCURRENCE 74/21C i
PaEo 1 of 4 OCCURRENCE DATE:
November 21. 1974 j
FORT ST. VRAIN NUCLEAR CENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 1
P. O. BOX 361 PLATTEVILLE, COLORADO 80651 i
j REPORT No. 50-267/74/21C j
FINAL SUPPLEMENT l
I)
IDENTIFICATION OF OCCURRENCE:
q j
On November 21, 1974, high pressure in the gas waste vacuum tank ruptured j
a rupture disc and lifted a relief valve allowing an unauthorized release i
of approximately 700 SCF of uncontaminated gas to the Reactor Building venti-l 1ation system. This wen identified as an abnormal occurrence per the Fort St. Vrain Technical Specifications, Section 2.1, Paragraph C.
I.
j CONDITIONS PRIOR TO OCCURRENCE: _
Steady State Power Routine Shutdown Hot Shutdown Routine Load Change II X
Cold Shutdown Other (specify)
Refueling Shutdown i
Routine Startup l
The major plant parameters at the time of the event were as follows:
a Power RTR N/A MWth ELECT N/A MWe j
Secondary Coolant Pressure N/A psig i
Temperature N/A
- F l
Flow N/A
- /hr.
Primary Coolant Pressure O
psig.
Temperature 135
'*F Core Inlet 8311170054 760903 135
- F Core Outlet PDR ADOCK 05000267 S
PDR J
Flow 0
f/hr.-
1
=
_. - - _ ~. _., - _ -
. ~...
o O
~
ABNORMAL OCCUPJ2NCE 74/21C 1
Page 2 of 4 DESCRIPTION OF OCCURRENCE:
i While venting down the helium purification reFeneration system, to the gas l
waste vacuum tank, at the conclusion of the regeneration of "A" low temperature adsorber, high pressure on "A" gas waste surge tank was alarmed. The reactor operator immediately switched to the "B" tank but the inlet valve (HV-6336) to "B" surge tank had been handjacked shut, ef fectively shutting off the dis-charge of the compressors. The resulting abrupt pressure increase in the vacuum tank caused the rupture disc and safety valve to be blown, releasing approximately 700 SCF of gas to the ventilation system exhaust. The venti-lation exhaust is monitored and these instruments showed no detectable change in count rate. Subsequent lab analysis of the "A" surge tank contents con-tained that no detectable activity was present in the gas.
APPARENT CAUSE OF OCCURRENCE:
X Design Unusual Service Cond.
Including Environment Manufacture Component Failure Ins tallation/ Cons t.
Other (specify)
X Operator i
X Procedure ANALYSIS OF OCCURRENCE:
Design: The isolation valves at the inlet to each gas waste surge tank have leaked in the past and a practice has been established to set the handjack on a valve during a release from the tank to prevent inleakage and release of unanalyzed gas. The handjack was set but not released af ter the tank was empty.
Operator: A hold tag should have been placed on the handswitch to alert the operator that the handjack on HV-6336 was set closed.
Procedure: The valve list does not specifically list a check of handjack re-moval or a test of valve operation.
CORRECTIVE ACTION:
l Design: A field change notice (FCN-GA-2642 "A") has been issued to replace C
the gas waste surge tank inlet isolation valves with Kerotest valves. A good I
seal in these valves will make the use of the handjacks unnecessary.
O O
4 ABNORMAL OCCURRENCE 74/21C 4
~
Page 3 of 4 l
l CORRECTIVE ACTION (continued):
Otange Notice #91 issued to change the wiring so either HV-6335 or HV-6336 3
will always be open has been cancelled. Field Change Notice.f2655 has been issued by General Atomic Company to interlock flow from the rageneration i
system with vacuum tank pressure to prevent overpressurization of the vacuum tank. Referring to the attached drawing, PV-2352 will close whenever the vacuum tank pressure reaches 13 psia as sensed by PSH-6315. This will pre-vent large additions to the gas waste system inventory from the regeneration system at a time when the vacuum tank is not being properly evacuated.
Operator: Operators have been issued a memo to place a " HOLD" tag on the j
tank selector switch when a handjack is set on either valve.
j Procedure: The system operating procedure valve list has been modified to call for handjack removal af ter the discharge is complete and includes a tes t of valve operation. This step will be removed af ter the sof t seat valves l
at the tank inlet are installed and proven to be leak free.
No further corrective action is planned or anticipated.
1
~
FAILURE DATA /SIMILAR REPORTED OCCURRENCES:
None PROGRAMMATIC IMPACT:
None a
CODE IMPACT:
None Submitted by:
fx.
J H. W. H111yary Jr.
/~
Technical Services Supervisor l
Reviewed by;
/r H. Larry Brey Superintendent, Operations Approved by:
w M
1%ederic E. Swart Superintendent, Nuclear Production i
i
~..
.t..
2 (3 4.q;, y.,,,.y.'
-... <. :-, r :.
. e, e.. z. w 1
\\BNORMAL OCCURRENCE 74/21C
/
Page 4 of 4 Puut !!ayicg cent
. - 7..,....
u....,. :
w.
.n P & I DI AGs.,,,,
-G r
... - HELIUG PURlFICATION o - u o.-........, ' '?.4, -
1 u
.".-5.
- g...-
( ' '#
' " " ~ " " - - - -
J E-2306 SYSTEM-REGENERATION s.
J-
'-P.**'
~ ~ ~
O_, y
_ REGENERATION SEC TION -
4 2
_ HEATER
.9 0 PI-23-3 Ur M...?E.Vf. R..O '.
., g. h.
- ~ s..r. =.,. -
20 7 c'.540Y e4s osicvs50Y
/p. EN. 2 3 197.5 -
.% m.
., ;ci l: 2.
, s,, ;s. *,
i g
-.,t - -
'i 6.,,5/*],,?'." S
%, ',. s, p.( ' r;.sy;;.g %.-(,, '.t.y '
. CUTY:47o,0 ccBTu/H4 4.C1,CtA55'C', J.
istgy: g, go psinfio$y
...,,., g' Q. A. DEPARTMENT..;3. ; 3..n,j...;.
.:.3 2l.w.
'W,i.gq.,
~. !SSUED. :.:: r.g c
1 v...ec
.ourter: s, r,os cv6sey 7-Y'
.P 9
/ Asut ecot: sccries m,etass c-
. 't...'. $,..:,, ;. : [:: >w..
- ..i..'%.:.,.W..
W 2'.-z?. "g.y.g_4 s.
- a.. '.
.k
.,k-
', M.. a %.. :',%w.h.
c y.
.m. :;&..
y. T ::.n 4.. p..: h..: i ' r.. :; i.q, :..n.:,-&:Sk'.C:
M,. p.-, c...... Q...,.:
- -;,,?
.,M -
- 1. 4.,.3. w.y.7, Ki.,: 1
...s r
....;;; y.
...:6,
- ... ;.c. a....,,..., g ;.
.o..
~
- n. -..
Csys~tc vc rurio.
...,..g,,,...,.
,. _.4 g
..-.__________..____._..._.,..__m;.._.;,.: y..g..:. 3.cc n..,
.u. c..
a.
n.,,
.%. s
..,. y,...y -;;.
.. n;.,
. g
... v;,\\. - i g..* *
+.'$.s.q.n:g.9..:-at.?S,.;,x.t..jr;;
- 1. d -.
T.
r
..s,.;
- -. n
- s.,
r.
,c=
.3"-
.. v..s n
n ns
',X.. ;.ys.'f..' *,. k.,. hb f.
..,, },. { ;.g; f. p.-
12 g.
.i.,
- ," :.. f
. I 22 'u2-8 3
~ ?.
l-
.. :.. l.
~' ' 1
'8r. "sL.
66 l
.... a. x uv x
.. g...
er 4 i
,n hp 9 L...i :. ]
.~. ti. m..m,, y,j,.1
,w,rs.
"d - " M '.: " )..'i h,.P.k.i. r d..$ 4-Q$
- a. -
r
- w. g,;~;.v...<.,,..t.
d
.. sea -
,, 3 34 3
..-n-
.m c
g,.,
s 0 'S u.
_yC -,
.o p+.
om s.so.
n P$ ti,.ny s $1 6J p.
3
- I.2 2 ' "
</
.se
~
T j l'cQ' )
- L. l. gv..
..7 i
/~E N
- I s
'<k..
a.
1 542-s -
.i
. p. -. s.. r..:~q r
. ~
.pd r. m /.,,,.
Fi[ <.vt23:27.czi$..
- .,y
- n.;
9 poso,Acrivt als".,,-
W rE SYSTE (.
/- M
_$,.,, ly_t23n -sq 2,3
,,..u3n3.c, i 4
h
]
-[a t2372 @ -pci - --
- " 8Y' '
' ' NQ
~ *"
4 (pi.63-1)(A 6) d (V2333) k 2WS Va cccim Ta nk N./
ri.
..t. ;..
sui is g s 34f.:g.y 34 5
......~..g_,.:_ t,. v. s...
y
+ '.,'
. +r.,,~,
. x.3.
e~:..
~
av y
2 m..
. e.., ;.
e
.v w
- s. :,... t..
.o
<....A~'*.-
.r
. r..
as a
g -,
un 1
'<,...,..3s*.
.,A..
.t.. e
=e.Q ag
~;.,
?
4 me
- e. n
....c' )
,....,.'s
.. y... r.-n em-en.
n.
o
~.
a
~
@:-Q
..'...,u.
t.
o 3
O
- g cm
-.~r.-
.... L
..,.~.:-
, sec'c as,
.. s...
c : :e
.c -
p23nv 2n
.... ;2 nw23m
.::..y -. w.
u.
.w J
.s.
u.
s t
w
.e
. g..rs
~~,
g g
. a
.. ft.
. ~..
1 i
riv e
W-(V2329 )
i,g,
.,f
. Q..,.
i
. Qa 's l
setisort e E.*
j (V2 331 )
b
.o.
E,(E2513 hi
~
'L* '
a r
n g.,'354.
Ff lY 3
e.a t 6 e.h NF d
r --- - -
l 3
vi r
e J'sf t
. y'5 (V 2 337 t. g ".H. e-1 t ".k.=l ).
f wao
! )3 SHUTS on HEAttR e
l gt; {..----s'-----
ON HIGH 1[uptqAyyqg PA
- v 23ro)
',. 4,". ;, - '
I.is2343 "I'
sEY e 845psic__
,,,,, p, 79
['
s.
p*,,,, ~ j l q'y,.8"k
, :,,i
.i
. i. o. fiv J,,n.t.,.,,, s,,
t e eq.,.u.. h, / 7 &,, y,.p.dm
,,,,gg.;,r.g po
.x.v e g.,
9 Il s ex m.s-
.34,
, i 2.
,e e
,.h,-
c' l
J
,..u
,,